The present invention relates to a flush valve. More particularly this invention concerns such a valve used in a toilet.
A standard toilet has a bowl and, at a location some-what above the bowl, a tank that normally is full of water that can be released into the bowl to flush the bowl, either through direct displacement or siphon action. The tank has a floor with an outlet port that is normally blocked by a ring mounted on an overflow tube whose upper end is above the normal liquid level in the tank. For flushing the overflow tube is raised, thereby allowing the water in the tank to rush out the outlet port while a float attached to the overflow tube holds it up off the outlet port until the tank is substantially empty, whereupon the tube reseats itself and the tank is slowly refilled by a float-controlled trolled fill valve.
Such systems are relatively failure prone. The seal at the outlet port can degrade and allow some leakage with the concomitant waste of water, or it can fail altogether so that the tank cannot fill. The overflow tube must align perfectly with the outlet port so that any problem with the mechanism can result in the flush valve not closing properly.
It is therefore an object of the present invention to provide an improved flush valve.
Another object is the provision of such an improved flush valve which overcomes the above-given disadvantages, that is which is certain to have a long leak-free service life.
A flush tank has a downwardly open outlet, a valve for filling the tank with a liquid, and a flush valve having according to the invention a tube fitted to the outlet and having an upper end vertically displaceable in the tank between an upper position and a lower position. A float fixed to the tube upper end and having an upwardly open compartment has a low buoyancy insufficient to hold the tube upper end above the liquid level when the compartment at least partially filled with water and a high buoyancy capable of holding the tube upper end above a liquid level in the tank when the compartment is empty. A vertically displaceable actuating rod extending along an upright axis has an externally accessible upper end and an actuating formation engageable vertically downward against the float to submerge same and fill the compartment so that when the compartment is filled the float is changed from high buoyancy to low buoyancy and the tube upper end sinks from the upper position below the liquid level and causes the liquid in the tank to flow through the tube out of the outlet. Stop formations on the tube and on the rod are engageable for limiting downward displacement of the float and tube to an intermediate position above the lower position and are disengageable to allow downward displacement of the float and tube into the lower position.
Thus this system allows the toilet to effect a small flush using only part of the contents of the flush tank, that is the amount allowed out on movement of the float from the upper to the intermediate position, or a large flush corresponding to the amount allowed out on movement of the float from the upper to the lower position. Thus it is possible to conserve water while still disposing of a large-volume flush when that is necessary.
The tube according to the invention is an accordion type cuff having a lower end fixed to the tank around the outlet and an upper end secured around the tube near the float.
The float in accordance with the invention has a lower part annularly surrounding the tube and an upper part forming the compartment and having a large upwardly open mouth level with the upper end of the tube and a small aperture below its mouth opening into the tube. The lower part is a downwardly open annular lower space. The upper space annularly surrounds the tube at the upper edge and is formed by an annular outer wall and an annular inner wall concentric therewith and forming a part of the tube. The small aperture is formed by a plurality of upwardly open slots formed in the inner wall.
According to the invention the upper part is formed as a funnel having an upper edge level with the upper tube end and a lower end in the tube. This funnel is coaxial with the tube and the actuating rod has a lower end extending down through and generally blocking the lower funnel end in only the upper position of the tube. The actuating member includes a spring urging the rod upward.
The tube upper end according to the invention forms a slot constituting one of the stop formations and through which the rod extends. The rod extends along and is rotatable about a vertical axis and is provided with a transversely extending stop that constitutes the other stop formation and that can pass axially and vertically through the slot in one angular position of the rod corresponding to a full flush and that is axially engageable with the tube at the slot in another angular position of the rod corresponding to a partial flush so that when the tube descends in the partial-flush position it comes to rest on and is stopped by the stop in the intermediate position.
Interengaging retaining formations are provided on the rod and stop for axially displacing and arresting the stop on the rod. These retaining formations are screwthreads. Furthermore the transversely extending stop includes a pair of opposite horizontal arms projecting from the rod. The tank has a top wall and the rod has a button projecting from the top wall and fixed to the upper rod end. The rod is rotatable about its axis in the button and is provided with a pointer. The button is provided with indicia alignable with the pointer to indicate the angular position of the rod.